Recently, with the increase of an data amount transmitted in accordance with the development of multimedia services, a packet communication system with a high communication speed has been developed. One of the examples is a system corresponding to a third generation partnership project radio access network long term evolution (3GPP LTE) that is a communication standard.
Currently, there are a plurality of communication networks. Thus, there is provided a multi-communication apparatus configured to perform communication using a plurality of communication systems corresponding to respective communication networks. The communication systems are exemplified by the above LTE system and third generation (3G) system, for example.
Some multi-communication apparatuses have a plurality of processors including a communication processor such as a communication central processing unit (CCPU) and an application processor such as an application central processing unit (ACPU), for example. When the multi-communication apparatus having a plurality of processors is switched from a first communication system to a second communication system, the communication processor first rebuilds a communication bearer from a first communication bearer corresponding to the first communication system to a second communication bearer corresponding to the second communication system. Then, the communication processor notifies, using a notification channel, the application processor of information of the rebuilt second communication bearer. Thereafter, the application processor reestablishes, using the information communicated by the communication processor, a connection between the processors from a first connection corresponding to the first communication bearer to a second connection corresponding to the second communication bearer. In this manner, it is possible to establish a connection corresponding to the communication bearer after rebuilding between the application processor and the communication processor, thus enabling communication in the second communication system. Here, the notification channel is a channel used for communicating control information between processors.
Recently, in mobile network services, what is called background communication has been performed. The background communication is a communication performed mainly by an application even without any user's operation, for example.
Conventionally, there is disclosed a technique of stopping notification from the communication processor to the application processor when a display screen is off. Thus, it is possible to stop notification processing while a user does not perform any operation, which can decrease power consumption of the communication processor and the application processor. A conventional example is described in Japanese Laid-open Patent Publication No. 2003-244316.
However, in case of the conventional technique, it is possible that when a request for background communication occurs while notification through the notification channel is stopped, the background communication cannot be performed. That is, while notification through the notification channel is stopped, the application processor cannot recognize such a fact, even when a communication bearer has been rebuilt. Consequently, the application processor tries background communication using a connection corresponding to a communication bearer before rebuilding. However, the communication bearer before rebuilding is already deleted and, as a result, the background communication cannot be performed.
When notification through the notification channel is not stopped, both the communication processor and the application processor operate constantly, which increases power consumption thereof.